In a mobile communication system, a base station and a mobile station communicate with each other. The base station may have large coverage and a large throughput, for example, a large amount of data transferred in unit time. Therefore, for example, the output power of the base station in downlink may be set to be large. Because a control signal is transmitted even when the amount of use of communication, for example, the amount of data transferred is small, the output power may not become small.
The related art is discussed in Japanese Laid-open Patent Publication No. 2000-197107 and other publications.